1. Field
The present invention relates to electronic substrate package technology, in particular a substrate package with through holes for high speed input/output (I/O) flex cables.
2. Discussion of Related Art
Traditionally, signals from a substrate package travel to another substrate package attached to a common motherboard via the sockets and motherboard. Signals traveling on this conventional path are susceptible to signal degradation and losses due to on-die parasitics, return loss and cross talks. Flex cable interconnection provides improved signal transmission quality and transfer rate.
FIG. 1A illustrates a cross sectional view of a known inter-package flex cable connection. Substrate package 120 includes die 104 attached to substrate body 102 via die bumps 105. Substrate package 120 is mounted on socket 108. Socket 108 has socket contacts 109 soldered to solder balls 110. Solder balls 110 are reflowed to form connection with motherboard 112. Substrate package 120 is interconnected with another substrate package 130 attached to motherboard 112 by way of flex cable 114. Flex cable 114 is attached to substrate packages 120, 130 by way of connector 106. Connector 106 is soldered permanently on substrate body 102 and forms part of substrate body 102. Signals between substrate packages 120, 130 are transmitted via flex cable 114 without having to route through socket 108 or motherboard 112.
FIG. 1B illustrates another known inter-package flex cable connection. In relation to substrate package 120, flex cable 114 is inserted between socket 108 and motherboard 112. One end of flex cable 114 is soldered to socket contacts 109 while the other end of flex cable 114 is soldered to the lands side of substrate package 130. This configuration is susceptible to signal degradation as signals from die 104 pass through plated through-holes (PTH) of substrate body 102.
Inter-package flex cable connections illustrated in FIGS. 1A and 1B involve some form of permanent attachment between component parts in the configuration. The configuration in FIG. 1A involves soldering between connector 106 and at the bottom surface of substrate package 120. The configuration in FIG. 1B involves soldering of flex cable 114 to socket 108. The known configurations do not provide complete separability of the component parts involved in the inter-package flex cable connection. Complete separability between the component parts is desirable to provide flexibility in the manufacturing and assembly of the component parts.